The class of polycarbonate polymers is broadly known in the art. An early review article by Schnell, Industrial and Engineering Chemistry, Vol. 51, No. 2, pp 157-160 (1960) describes properties of the class of polycarbonates and methods known in the art at that time for the production of polycarbonate polymers including certain polycarbonate polymers which are now commercial. In general, the polycarbonates are thermoplastics whose glass transition temperatures will depend upon the nature and the symmetry of the groups incorporated into the polycarbonate chain other than the carbonyldioxy groups. Most polycarbonates are derived from a bisphenol and commercial polycarbonates are derived from a 2,2-di(4-hydroxyphenyl)propane, also known as bisphenol A or BPA. The polycarbonate polymers are conventionally produced by reaction of a bisphenol or an alkali metal salt thereof with phosgene or by ester exchange with a diaryl carbonate, particularly diphenyl carbonate.
These polymers are processed by conventional methods employed for thermoplastics such as injection molding or extrusion into films, sheets, fibers, tubing and shaped articles. The articles produced from polycarbonate polymers demonstrate good resistance to oxygen, heat and light as well as resistance to common solvents.
The properties of many thermoplastics is raised by the incorporation of cyclic structures or additional cyclic structures within the polymer chain. One such class of polycarbonate polymers is described and claimed by copending U.S. patent application Ser. No. 279,671, filed Dec. 5, 1988, now U.S. Pat. No. 4,906,725. This application claims an alternating polycarbonate polymer wherein moieties of an oxyaryl-substituted spirodilactam, i.e., a 1,6-di(oxyaryl)-1,6-diazaspiro[4.4]nonane-2,7-dione, alternate with carbonyl moieties. In an optional embodiment, a portion of the moiety derived from the spirodilactam bisphenol is replaced with a moiety derived from a di(hydroxyphenyl)alkane such as BPA. The polymers are produced by the conventional reaction of phosgene or diaryl carbonate with the bisphenol(s) or alkali metal salts thereof. In the polymers of this copending application Ser. No. 279,671, moieties of bisphenol alternate with carbonyl moieties. However, in the embodiment where moieties of two bisphenols are present, the relationship of the two bisphenol moieties is random. It would be of advantage to provide polycarbonate polymers of mixed bisphenol moieties wherein the relationship of the bisphenol moieties is regular and alternating. Such polymers are known to have greater hydrolytic stability than polycarbonate polymers having a random arrangement of bisphenol structures. See U.S. Pat. No. 4,595,404, for example.